Using synchronization frames for mesh networking with piconets

ABSTRACT

Certain aspects provide a technique for managing transmissions in a wireless network. The technique generally provides for an access terminal to transmit synchronization packets containing timing information regarding an existing piconet. The synchronization packets may contain an indication of resources of the piconet allocated to the access terminal by an access point.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit of U.S. Provisional Patent ApplicationSer. No. 61/113,436 filed Nov. 11, 2008, which is herein incorporated byreference in its entirety.

BACKGROUND

1. Field

The invention relates generally to wireless communication and, moreparticularly, to wireless networks, such as local area networks (LANs)and personal area networks (PANs) commonly referred to as piconets.

2. Background

A “piconet” is generally defined as a wireless personal area networkthat is composed of a group of wireless devices such as an “accessterminal,” an “access point” or both such devices in close proximity toone another. A piconet is typically controlled by an access point thatassumes the role of a Piconet Coordinator (PNC) that acts as a masterterminal that schedules access to the communications medium for theother access terminals in its piconet. Frames are the basic unit of datatransport in a piconet, which can include data, acknowledgment, beaconand MAC command frames.

A PNC may also define a superframe structure consisting of multipleframes, with beacons acting as boundaries and providing synchronizationto other devices. The IEEE 802.15.3 standard specifies that the PNCsends a beacon to synchronize data exchanges between the PNC and theterminals in the piconet. The beacon signals a start of a superframe andallows each terminal to reset its superframe clock to zero at thebeginning of a beacon preamble.

Certain drafts of the IEEE 802.15.3 standard mandate that all PNCcapable devices, when operating as PNC, shall transmit common ratebeacon in every superframe and that all PNC capable devices shall beable to receive the common rate beacon and command frames. Thismechanism is designed to allow PNC capable devices to become aware ofexisting piconets, which will allow them to join and, more importantly,prevent them from forming independent piconets that may causeinterference to devices that are in range of both piconets.

Unfortunately, a PNC capable device within range of some devices of anexisting piconet may not be in range of the piconet's PNC. As a result,such a device (which may be referred to as a “hidden node”) may notdetect the beacon preventing it from joining the existing piconet. Evenmore problematic, the hidden node may form an independent piconet andcause interference to devices that are in range of both piconets.

SUMMARY

Certain aspects of the present disclosure provide a method of wirelesscommunication. The method generally includes receiving, from a firstnode in a first piconet, a first synchronization packet containingtiming information regarding allocation of resources in the firstpiconet, determining interference time slots corresponding to allocatedtransmissions times for nodes in the first piconet, based on the timinginformation, and establishing a second piconet by allocating availableresources to nodes in the second piconet based on the determinedinterference time slots corresponding to allocated transmissions timesfor the nodes in the first piconet.

Certain aspects of the present disclosure provide an apparatus forwireless communication. The apparatus generally includes a receiverconfigured to receive, from a first node in a first piconet, a firstsynchronization packet containing timing information regardingallocation of resources in the first piconet, a scheduler configured todetermining interference time slots corresponding to allocatedtransmissions times for nodes in the first piconet, based on the timinginformation, and logic configured to establish a second piconet byallocating available resources to nodes in the second piconet based onthe determined interference time slots corresponding to allocatedtransmissions times for the nodes in the first piconet.

Certain aspects of the present disclosure provide an apparatus forwireless communication. The apparatus generally includes means forreceiving, from a first node in a first piconet, a first synchronizationpacket containing timing information regarding allocation of resourcesin the first piconet, means for determining interference time slotscorresponding to allocated transmissions times for nodes in the firstpiconet, based on the timing information, and means for establishing asecond piconet by allocating available resources to nodes in the secondpiconet based on the determined interference time slots corresponding toallocated transmissions times for the nodes in the first piconet.

Certain aspects of the present disclosure provide a wireless nodecapable of assuming a role of a Piconet Coordinator (PNC). The wirelessnode generally includes at least one antenna, a receiver configured toreceive via the at least one antenna, from a first node in a firstpiconet, a first synchronization packet containing timing informationregarding allocation of resources in the first piconet, a schedulerconfigured to determining interference time slots corresponding toallocated transmissions times for nodes in the first piconet, based onthe timing information, and logic configured to establish a secondpiconet by allocating available resources to nodes in the second piconetbased on the determined interference time slots corresponding toallocated transmissions times for the nodes in the first piconet.

Certain aspects of the present disclosure provide a computer-programproduct for communications, comprising a computer-readable mediumcomprising instructions. The instructions are generally executable toreceive, from a first node in a first piconet, a first synchronizationpacket containing timing information regarding allocation of resourcesin the first piconet, determine interference time slots corresponding toallocated transmissions times for nodes in the first piconet, based onthe timing information, and establish a second piconet by allocatingavailable resources to nodes in the second piconet based on thedetermined interference time slots corresponding to allocatedtransmissions times for the nodes in the first piconet.

Certain aspects of the present disclosure provide a method of wirelesscommunication. The method generally includes performing rangingoperations for a destination node that is to receive wirelesslydistributed video and adjusting at least one of a bandwidth orresolution of the wirelessly distributed video based on results of theranging operations.

Certain aspects of the present disclosure provide an apparatus forwireless communication. The apparatus generally includes ranging logicconfigured to perform ranging operations for a destination node that isto receive wirelessly distributed video and adjusting logic configuredto adjust at least one of a bandwidth or resolution of the wirelesslydistributed video based on results of the ranging operations.

Certain aspects of the present disclosure provide an apparatus forwireless communication. The apparatus generally includes means forperforming ranging operations for a destination node that is to receivewirelessly distributed video and means for adjusting at least one of abandwidth or resolution of the wirelessly distributed video based onresults of the ranging operations.

Certain aspects of the present disclosure provide a wireless videosource. The wireless video source generally includes at least oneantenna, ranging logic configured to perform ranging operations, basedon packets received via the at least one antenna, for a destination nodethat is to receive wirelessly distributed video, and adjusting logicconfigured to adjust at least one of a bandwidth or resolution of thewirelessly distributed video based on results of the ranging operations.

Certain aspects of the present disclosure provide a computer-programproduct for communications, comprising a computer-readable mediumcomprising instructions. The instructions are generally executable toperform ranging operations for a destination node that is to receivewirelessly distributed video and adjust at least one of a bandwidth orresolution of the wirelessly distributed video based on results of theranging operations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example piconet, in accordance with certainaspects of the present disclosure.

FIG. 2 illustrates example components of a piconet terminal, inaccordance with certain aspects of the present disclosure.

FIG. 3 illustrates an example piconet with nearby terminals that are notincluded in the piconet.

FIG. 4 is a conceptual diagram illustrating an example of interferencebetween terminals in a piconet and nearby terminals that are notincluded in the piconet.

FIG. 5 illustrates example operations for transmitting a unifiedsynchronization packet, in accordance with certain aspects of thepresent disclosure.

FIG. 5A illustrates example components capable of performing theoperations shown in FIG. 5.

FIG. 6 illustrates example operations for processing a detected unifiedsynchronization packet, in accordance with certain aspects of thepresent disclosure.

FIG. 6A illustrates example components capable of performing theoperations shown in FIG. 6.

FIG. 7 illustrates an example of a piconet that is virtually dependenton another piconet, in accordance with certain aspects of the presentdisclosure.

FIG. 8 illustrates an example synchronization frame format, inaccordance with certain aspects of the present disclosure.

FIG. 9 illustrates an example synchronization frame body format, inaccordance with certain aspects of the present disclosure.

FIG. 10 illustrates an example synchronization parameters field format,in accordance with certain aspects of the present disclosure.

FIG. 11 illustrates an example of a candidate piconet coordinator (PNC)using synchronization frames to detect the presence of an existingpiconet.

FIG. 12 illustrates example operations for scheduling synchronizationframe transmissions, in accordance with certain aspects of the presentdisclosure.

FIG. 12A illustrates example components capable of performing theoperations shown in FIG. 12.

FIG. 13 illustrates an example of multiple virtually dependent piconets,in accordance with certain aspects of the present disclosure.

FIG. 14 illustrates an example range calculation using synchronizationpacket time stamps, in accordance with certain aspects of the presentdisclosure.

FIG. 15 illustrates example operations for ranging, in accordance withcertain aspects of the present disclosure.

FIG. 15A illustrates example components capable of performing theoperations shown in FIG. 15.

DETAILED DESCRIPTION

Various aspects of certain aspects of the present disclosure aredescribed below. It should be apparent that the teachings herein may beembodied in a wide variety of forms and that any specific structure,function, or both being disclosed herein is merely representative. Basedon the teachings herein one skilled in the art should appreciate that anaspect disclosed herein may be implemented independently of any otheraspects and that two or more of these aspects may be combined in variousways. For example, an apparatus may be implemented or a method may bepracticed using any number of the aspects set forth herein. In addition,such an apparatus may be implemented or such a method may be practicedusing other structure, functionality, or structure and functionality inaddition to or other than one or more of the aspects set forth herein.Furthermore, an aspect may comprise at least one element of a claim.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any aspect described herein as “exemplary”is not necessarily to be construed as preferred or advantageous overother aspects.

In the following detailed description, various aspects of the inventionmay be described in the context of a wireless network or “piconet” inaccordance the IEEE 802.15 family of standards (whether adopted orproposed). While these inventive aspects may be well suited for use withsuch networks in which an access point (AP) may serve as a piconetcoordinator (PNC), those skilled in the art will readily appreciate thatthese inventive aspects are likewise applicable for use in various othercommunication environments utilizing any type of access points (APs) andaccess terminals (ATs), including, but not limited to, networks inaccordance with IEEE 802.11 family of standards and may, in fact, allownetworks in accordance with different standards to better co-exist.Accordingly, any reference to an IEEE 802.15 compliant network isintended only to illustrate the inventive aspects, with theunderstanding that such inventive aspects have a wide range ofapplications.

The teachings herein may be incorporated into (e.g., implemented withinor performed by) a variety of wired or wireless apparatuses (e.g.,nodes). In some aspects, a node implemented in accordance with theteachings herein may comprise an access point or an access terminal.

An access point (“AP”) may comprise, be implemented as, or known asNodeB, Radio Network Controller (“RNC”), eNodeB, Base Station Controller(“BSC”), Base Transceiver Station (“BTS”), Base Station (“BS”),Transceiver Function (“TF”), Radio Router, Radio Transceiver, BasicService Set (“BSS”), Extended Service Set (“ESS”), Radio Base Station(“RBS”), or some other terminology.

An access terminal (“AT”) may comprise, be implemented as, or known asan access terminal, a subscriber station, a subscriber unit, a mobilestation, a remote station, a remote terminal, a user terminal, a useragent, a user device, user equipment, or some other terminology. In someimplementations, an access terminal may comprise a cellular telephone, acordless telephone, a Session Initiation Protocol (“SIP”) phone, awireless local loop (“WLL”) station, a personal digital assistant(“PDA”), a handheld device having wireless connection capability, orsome other suitable processing device connected to a wireless modem.Accordingly, one or more aspects taught herein may be incorporated intoa phone (e.g., a cellular phone or smart phone), a computer (e.g., alaptop), a portable communication device, a portable computing device(e.g., a personal data assistant), an entertainment device (e.g., amusic or video device, or a satellite radio), a global positioningsystem device, or any other suitable device that is configured tocommunicate via a wireless or wired medium.

In some aspects, the node is a wireless node. Such wireless nodes mayprovide, for example, connectivity for or to a network (e.g., a personalarea network or piconet, wide area network such as the Internet, or acellular network) via a wired or wireless communication link.

An Example Piconet

FIG. 1 illustrates an example piconet, Piconet 1. As shown, Piconet 1may include a number of wireless devices 102 or “terminals” 1A-1E thatcan communicate with one another using relatively short-range wirelesslinks 104. In the illustrated example, terminal 1E acts as a PNC forPiconet 1. Although illustrated with five devices, it should beappreciated that any number of devices (i.e., two or more) may form awireless personal area network.

Each of the terminals 102 in the Piconet 1 may include, among otherthings, a wireless transceiver to support wireless communication andcontroller functionality to manage communication with the network. Thecontroller functionality may be implemented within one or more digitalprocessing devices. The wireless transceiver may be coupled to one ormore antennas to facilitate the transmission of signals into and thereception of signals from a wireless channel. Any type of antennas maybe used including, for example, dipoles, patches, helical antennas,antenna arrays, and/or others.

The devices in the Piconet 1 may include any of a wide variety ofdifferent device types including, for example, laptop, desktop, palmtop,or tablet computers having wireless networking functionality, computerperipherals having wireless networking capability, personal digitalassistants (PDAs) having wireless networking capability, cellulartelephones and other handheld wireless communicators, pagers, wirelessnetwork interface modules (e.g., wireless network interface cards, etc.)incorporated into larger systems, multimedia devices having wirelessnetworking capability, audio/visual devices having wireless networkingcapability, home appliances having wireless networking capability,jewelry or other wearable items having wireless networking capability,wireless universal serial bus (USB) devices, wireless digital imagingdevices (e.g., digital cameras, camcorders, etc.), wireless printers,wireless home entertainment systems (e.g., DVD/CD players, televisions,MP3 players, audio devices, etc.), and/or others. In one configuration,for example, a wireless personal area network may include a user'slaptop computer that is wirelessly communicating with the user'spersonal digital assistant (PDA) and the user's printer in a short-rangenetwork. In another possible configuration, a wireless personal areanetwork may be formed between various audio/visual devices in, forexample, a user's living room. In yet another configuration, a user'slaptop computer may communicate with terminals associated with otherusers in a vicinity of the user. Many other scenarios are also possible.

Standards have been developed, and are currently in development, toprovide a framework to support development of interoperable productsthat are capable of operating as part of a wireless personal areanetwork (e.g., the Bluetooth standard (Specification of the BluetoothSystem, Version 1.2, Bluetooth SIG, Inc., November 2003), the IEEE802.15 standards, etc.). The IEEE 802.15.3 standard, for example, is ahigh data rate wireless personal area network standard. In accordancewith the IEEE 802.15.3 standard, one of the terminals within a piconetis selected as a Piconet Coordinator (PNC) to coordinate the operationof the network. For example, with reference to FIG. 1, the device PNC lErepresents a PNC for the Piconet 1 in an IEEE 802.15.3 implementation.

As shown, PNC lE may transmit a beacon signal 110 (or simply “beacon”)to other devices of Piconet 1, which may help the other terminals withinPiconet 1 synchronize their timing with PNC 1E. Thus, the beacon,typically sent at the beginning of every superframe, containsinformation that may be used to time-synchronize the terminals in thepiconet. Each terminal in the piconet, including the PNC, may reset itssuperframe clock to zero at the beginning of the beacon preamble. If aterminal does not hear a beacon, it may reset its superframe clock tozero at the instant where it expected to hear the beginning of thebeacon preamble (e.g., based on previous superframe timing).

Example Terminal Components

FIG. 2 illustrates example components of a terminal 102 capable ofperforming operations in accordance with certain aspects of the presentdisclosure. As those skilled in the art will appreciate, the preciseconfiguration of the terminal 102 may vary depending on the specificapplication and the overall design constraints and any suitablecombination of components capable of performing the operations presentedherein may be utilized.

In the example configuration illustrated, the terminal 102 may beimplemented with a front-end transceiver 200 coupled to an antenna 210.A baseband processor 220 may be coupled to the transceiver 200. Thebaseband processor 220 may be implemented with a software basedarchitecture, or another type of architecture. The software basedarchitecture may configured with a microprocessor (not shown) thatserves as a platform to run software programs that, among other things,provide executive control and overall system management functions thatallow the terminal to operate either as a master or member terminal in apiconet. The baseband processor 220 may also include a digital signalprocessor (DSP) (not shown) with an embedded communications softwarelayer which runs application specific algorithms to reduce theprocessing demands on the microprocessor. The DSP may be used to providevarious signal processing functions such as pilot signal acquisition,time synchronization, frequency tracking, spread-spectrum processing,modulation and demodulation functions, and forward error correction.

The baseband processor 220 is shown with the transceiver 200. Thetransceiver 200 may include a receiver 202. The receiver 202 providesdetection of desired signals in the presence of noise and interference.The receiver 202 may be used to extract the desired signals and amplifythem to a level where information contained in the received signal canbe processed by the baseband processor 220.

The transceiver 200 may also include a transmitter 204. The transmitter204 may be used to modulate information from the baseband processor 220onto a carrier frequency. The modulated carrier may be upconverted to anRF frequency and amplified to a sufficient power level for radiationinto free space through the antenna 210.

The baseband processor 220 may be responsible for configuring theterminal as a master or member terminal of the piconet depending on theresults of the pilot signal acquisition process. When the basebandprocessor 220 configures the terminal as a member terminal of thepiconet, a signal processor 228 on the receiving end may be used toextract scheduling information broadcast by the piconet master terminalover one or more control channels. The signal processor 228 may usespread-spectrum processing, in conjunction with digital demodulation andforward error correction techniques, to extract the pertinent schedulinginformation from the control channel and provide it to a controller 230for processing. The controller 230 may use the scheduling information todetermine the time slots for the various transmissions to and from themember terminal, as well as the power level and data rate for each.

In the receive mode, the controller 230 may be used to provide data rateand spreading information to the signal processor 228 on the receivingend for the scheduled transmissions to the member terminal. Using thisinformation, the signal processor 706 may recover information embeddedin the transmissions from other terminals at the appropriate times andprovide the recovered information to the various user interfaces.

A signal processor 228 on the transmitting end may be used to spreadinformation destined for various other terminals. The information may beoriginated from various user interfaces and stored in a buffer 222 untilthe scheduled transmission. At the scheduled time, the controller 230may be used to release the information from the buffer 222 to the signalprocessor 228 for spread-spectrum, processing. The signal processor 228may also employ digital modulation and forward error correctiontechniques. The data rate, spreading code and power level of thetransmission may be programmed into the signal processor 228 by thecontroller 230. Alternatively, the transmission power level may beprogrammed by the controller 230 at the transmitter 204 in thetransceiver 200.

When the baseband processor 220 configures the terminal as the masterterminal of the piconet, it may enable a scheduler 224. In asoftware-based implementation of the baseband processor 220, thescheduler 224 may be a software program running on the microprocessor.However, as those skilled in the art will readily appreciate, thescheduler 224 is not limited to this aspect, and may be implemented byother means known in the art, including a hardware configuration,firmware configuration, software configuration, or combination thereof,which is capable of performing the various functions described herein.

The scheduler 224 may be used to generate scheduling information tosupport intra-piconet communications. The scheduling information may bederived based on any number of considerations and/or in accordance withany known scheduling algorithm. By way of example, schedulinginformation may be made based on a priority system, where voicecommunications are given priority over high latency communications. Thescheduler 224 may also give priority to high data rate transmissions inan effort to maximize throughput. Further increases in throughput may beachieved by scheduling parallel transmissions using spread-spectrumtechniques. By carefully selecting the terminal pairs that will engagein parallel communications, intra-piconet piconet interference may bemanaged. A fairness criterion that considers the amount of data to betransferred between terminal pairs and the delay already experienced bysuch terminal pairs may also be considered. Other factors may beconsidered and are within the scope of the invention. Those skilled inthe art will be readily able to adapt existing scheduling algorithms toany particular piconet application.

Overcoming Limitations of Standard Beacons

FIG. 3 is a conceptual diagram illustrating an example of a piconet 100(Piconet 1) having nearby terminals 102 that are not included in thepiconet. The piconet 100 may be considered a mesh network with a partialmesh topology. A partial mesh network generally refers to a local areanetwork (LAN) that has some nodes that are connected to all the others(e.g., PNC) and some nodes (e.g., DEVs) that are connected only to thoseother nodes with which they exchange the most data. As will be describedherein, the transmission of synchronization packets containing piconettiming information may be used to help establish and maintain such meshnetworks.

The illustrated example assumes the nearby terminals PNC 2A, DEV 2X, andDEV 2Y are located in relatively close proximity to Piconet 1, but thatPNC 2A is outside the range of transmissions from PNC 1E. The examplefurther assumes that PNC 2A is in transmission range of DEV 1C and DEV1D.

Since PNC 2A does not receive any beacon signals 110 from PNC lE (asindicated by the “X” in FIG. 3), PNC 2A is unaware of frequency/timeslot assignments within Piconet 1. As a result, PNC 2A may thus attemptto transmit in one or more of the frequency/time slots assigned withinPiconet 1. For example, unaware of Piconet 1, PNC 2A may form a secondpiconet, Piconet 2, with terminals 2X and 2Y. The formation of Piconet 2may result in an interference zone 300 where transmissions fromterminals in the different piconets may interfere. In the illustratedexample, terminals 1C and 1D included in Piconet 1 are also within rangeof Piconet 2 and may, thus, experience interference due to conflictingtransmissions from Piconet 2 in the same frequency/time slots.

Certain aspects of the present disclosure, however, may overcome thisproblem by having all types of terminals included in a piconet (e.g.,not just terminals acting as a PNC) transmit beacon signals, referred toherein as unified synchronization packets including synchronization datafor the piconet. By having all types of terminals transmitsynchronization packets, the range of devices capable of detecting anexisting piconet (and the resources allocated to terminals of theexisting piconet) may be significantly increased relative to thestandard situation with only the PNC transmitting synchronizationbeacons. In other words, nodes that were previously “hidden” from thePNC of a nearby piconet may learn of the piconet via detection of thesesync packets transmitted from non-PNC terminals within range. As aresult, the unified synchronization packets may help terminals inproximity of an existing piconet avoid transmitting in the samefrequency/time slots allocated to devices in the existing piconet andmay, thus, help reduce interference and help support coexistence ofadjacent networks.

FIG. 4 illustrates synchronization packets 120 being transmitted fromall non-PNC terminals in a piconet to reduce transmission interferencebetween a piconet and nearby terminals, in accordance with certainaspects of the present disclosure. As illustrated terminals acting asPNCs (e.g., PNC 1E and PNC 2A) may continue to transmit conventionalbeacon signals.

As shown, each non-PNC terminal (e.g., DEV 1A, DEV 2X, etc.) transmits asynchronization packet, or “sync packet.” Such sync packets may betransmitted alone or as part of other transmissions (e.g., data frames).Each terminal may transmit a single sync packet, or may transmitmultiple sync packets. For example, the terminal may transmit a syncpacket upon receiving an allocated/assigned frequency/time slot from aPNC, may transmit a sync packet between every superframe, may transmitin a repeating time cycle, may transmit according to fixed schedule, andthe like.

For certain aspects, sync packets may be sent in a manner that allowsterminals having a variety of different types of physical layers (PHY)detect them. For example, the IEEE 802.15.3c defines various PHY modes,and devices may be configured to transmit sync packets using a singlecarrier (SC) that may be detectable by other devices (even if theynormally operate in an OFDM mode). Such “unified” sync packets may alsohelp promote the co-existence of networks with different PHY layers. Forexample, sync packets may be sent from IEEE 802.15 compliant devices ina manner that allows both IEEE 802.15 compliant and IEEE 802.11compliant devices to detect them. For certain aspects, this may allowdevices, such as those compliant with the proposed IEEE 802.11 VHT60standard with IEEE 802.11 PHY and Medium Access Control (MAC) Layers, tooperate in the 60 GHz frequency band (typically 57-66 GHz) with veryhigh throughput, while coexisting with IEEE 802.15.3c systems (and withother systems operating in a similar band).

For certain aspects, each terminal (e.g., PNC-capable and nonPNC-capable terminals) may be configured to scan for and detect syncpackets and/or beacon signals. For certain aspects, only PNC-capableterminals may be configured to scan for and detect sync packets and/orbeacon signals. In any case, by receiving such synchronizationinformation, a terminal can learn of an existing piconet. Further, thereceiving terminal may use the synchronization information to avoidinterfering with the existing piconet.

For example, referring to FIG. 4, PNC 2A may receive sync packets 120transmitted by DEV 1C and/or DEV 1D. Because these sync packets mayinclude synchronization information regarding timing and resourceallocation for Piconet 1, PNC 2A may avoid transmissions that wouldcause interference to devices in Piconet 1. For example, PNC 2A maycontrol transmissions to/from DEV 2X and DEV 2Y so they avoidfrequency/time slots assigned within Piconet 1, thereby reducing oreliminating any interference with Piconet 1. To accomplish this, the PNC2A may synchronize its timing with the timing of PNC 1.

FIG. 5 is a flow diagram illustrating operations 500 for transmitting aunified synchronization packet, in accordance with certain aspects ofthe present disclosure. FIG. 5 illustrates operations performed, forexample, by a non-PNC device included in a piconet.

For the sake of illustration, the operations are described below inconjunction with the example illustrated in FIG. 4. The operations beginat 510, where a non-PNC terminal receives an allocation of transmissionresources in a piconet. For example, DEV 1C may receive an allocation offrequency/time slots within Piconet 1 from PNC 1E.

At 520, the terminal may transmit a unified synchronization packetcontaining information regarding the allocation of resources within thepiconet. An example of a unified synchronization packet, its format, andthe information contained therein, is described below with reference toFIGS. 8-10.

At 530, the terminal may send transmissions according the resourceallocation received at 510. A terminal may send sync packets at anysuitable time. For certain aspects, a terminal may transmit whenreceiving an allocation for transmission. For example, in the case of an802.15.3c device, each device may send a synchronization packet at leastat the first time it receives an allocation to transmit (e.g., includingan allocation for ACK packet). As a result, devices that receive thesesync packets may become aware of the piconet, even if they are not inrange to receive beacons from the piconet PNC.

FIG. 6 illustrates example operations for processing a unifiedsynchronization packet, in accordance with certain aspects of thepresent disclosure. For example, the operations of FIG. 6 may beperformed by a PNC device not included in an existing piconet of aterminal that transmitted the synchronization packet.

The operations begin at 610, when a PNC learns of the existence of anexisting piconet through the detection of a unified synchronizationpacket sent from one or more terminal devices of the existing piconet.For example, referring to FIG. 4, PNC 2A may receive a sync packet sentby DEV 1C or DEV 1D, and may thus learn of the existence of Piconet 1.

At 620, the PNC determines a superframe start time and durationcorresponding to the existing piconet based on information contained inthe unified synchronization packet. The PNC may use such synchronizationinformation to avoid sending transmissions that interfere with Piconet1. For certain aspects, there may be no fixed timing requirements forexactly when to send a synchronization packet. Therefore, in order toallow a receiving terminal to determine timing information (such as thestart of a superframe) of the existing piconet, the sync packet mayinclude a timestamp indicating when the sync packet is sent. The timestamp may be generated by the device sending the sync packet, forexample, based on an internal counter reset at the start of a superframewhen a beacon signal is received. A device receiving a sync packet maythus be able to determine the start time of a superframe of the existingpiconet based on the time stamp.

For certain aspects, a PNC receiving a synchronization packet may usethe information contained therein about an existing piconet to establisha piconet that is “virtually dependent” on the existing piconet,generally meaning that the piconet may coexists with an existing piconetby avoiding using allocated resources of the existing piconet. The PNCmay establish a virtually dependent piconet, such as Piconet 2illustrated in FIG. 7, for example, by performing optional operations630 and 640.

At 630, the PNC may determine resources allocated to devices in theexisting piconet based on information received in the unifiedsynchronization packet. At 640, the PNC may establish a virtuallydependent piconet using resources that are not allocated in the existingpiconet. As will be described in greater detail below, thesynchronization packet may include Channel Time Allocation (CTA)information elements (IEs) indicating resources allocated to terminalsin the existing piconet.

For example, referring to FIG. 7, PNC 2A may determine resourceallocation information for Piconet 1 from information in a sync packet120 sent by DEV 1C or DEV 1D. PNC 2A may then establish Piconet 2 asbeing virtually dependent on Piconet 1, using available resources thatare not already allocated in Piconet 1.

According to certain aspects, a PNC may perform a periodic scan of theCTA IEs of neighboring piconets (included in the sync packets) to mapand mask interference zones as part of virtual dependent piconetmaintenance. For example, through these periodic scans, the PNC maylearn of changes to resource allocation in the existing piconet and makecorresponding adjustments to resource allocations in the virtuallydependent piconet.

FIG. 8 illustrates an example format 800 of a sync packet. The formatmay be similar or the same as a synchronization frame format used forsynchronization frames (beacon signals) sent according the IEEE802.15.3c standard. As shown, the synchronization frame format 800 mayinclude a long preamble, a header, a Header Check Sequence (HCS), a setof parity bits, a synchronization frame body, and a Frame Check Sequence(FCS). The synchronization frame body may include synchronizationinformation regarding an existing piconet, as well as an indication ofresources allocated in the existing piconet.

FIG. 9 illustrates an example format of the synchronization frame bodyof the sync packet. In this example, the synchronization frame bodyformat 900 may be similar to or the same as a synchronization frameformat according to the IEEE 802.15.3c standard. As shown, thesynchronization frame body format 900 may include synchronizationparameters and Channel Time Allocation (CTA) information elements. Forexample, the CTA information elements may include frequency/time slotsassigned to each terminal of a piconet. As described above, aPNC-capable device receiving the CTA IEs may use the informationcontained therein to identify resources available for allocation toterminals in a virtually dependent piconet.

FIG. 10 illustrates example fields 1000 that may be included in theSynchronization Parameters, in accordance with certain aspects of thepresent disclosure. In this example, the synchronization parameters 1000may include certain fields that are also used in the IEEE 802.15.3cstandard. As illustrated, the synchronization parameters 1000 mayinclude a superframe number, a superframe duration, a contention accessperiod (CAP) end time, a frame start time, a reserved field, and aPiconet Coordinator (PNC) address.

The frame start time may include the time stamp described above,indicating when the sync packet was sent relative to the start of asuperframe in the existing piconet. For example, since the common rate(CR) beacon in a piconet is transmitted by the PNC at the start (t=0) ofthe superframe, and the timing of sending sync packets by non-PNCterminals is not fixed (e.g., each device may only be required to send asynchronization packet at least at the first time its get allocation totransmit), the frame start time may be introduced.

This field provides the time stamp for the synchronization frame andmarks the synchronization frame preamble start time. Thus, a PNCreceiving the sync packet may use this time stamp to determine the startof a frame preamble and may then schedule data transfers in a mannerthat helps avoids interference with the existing piconet.

Thus, referring to FIG. 7, even though PNC 2A may not detect beaconsignals 110 from PNC 1E, it may use information in the sync packets 120from DEV 1C and DEV 2C to synchronize data transfers accordingly andform a virtually dependent piconet, Piconet 2. In so doing, PNC 2A mayschedule data transfers for members of Piconet 2 (DEV 2X and DEV 2Y) ina manner that avoids interference with data transfers on Piconet 1.

Example Network Detection of and Synchronization

As illustrated in FIG. 11, a candidate PNC may periodically scan forsync frames transmitted from devices in neighboring networks. Thecandidate PNC may then use the timing information contained in the syncframes, to synchronize to its own timing. For example, the candidate PNCmay determine “interference time slots” corresponding to allocatedtransmission times for devices in an existing piconet and allocateresources to devices in its own piconet in an effort to avoid theseinterference time slots. As long as the networks remain timesynchronized, as is the case with virtually dependent piconets, theinterference zone should remain constant in the time domain and the“interference time slots” can be marked for each neighboring networkelement.

FIG. 12 illustrates example operations for scheduling synchronizationframe transmissions, in accordance with certain aspects of the presentdisclosure. For example, the operations may be performed by a PNC orcandidate PNC to detect a neighbor piconet and adjust allocation ofresources to its own piconet devices in an effort to avoid interference.

The operations begin, at 1202, with the PNC receiving, from a first nodein a first piconet, a first synchronization packet containing timinginformation regarding allocation of resources in the first piconet. At1204, the PNC determines interference time slots corresponding toallocated transmissions times for nodes in the first piconet, based onthe timing information. At 1206, the PNC may establish a second piconetby allocating available resources to nodes in the second piconet basedon the determined interference time slots corresponding to allocatedtransmissions times for nodes in the first piconet.

In this manner, the PNC may utilize synchronization packets it receivesfrom devices in an existing piconet to synchronize its timing to theexisting piconet and form a virtually dependent piconet.

As illustrated in FIG. 13, multiple virtually dependent networks may becombined to form a mesh network. In the illustrated example, PNC3utilizes synchronization packets it receives from devices in piconet2 tosynchronize to PNC1 timing and forming a virtually dependent piconet 3.

Each PNC may schedule periodic scans of devices in its own network todetect interference and/or use data received from sync packets ofdevices in neighboring networks to calculate range from neighboringdevices. As described above, each PNC may determine and map an“interference time slot” for each network element. Each PNC may thenschedule data transfers for devices in its own on piconet in a mannerthat avoids interference between the piconets.

The total bandwidth used in a mesh network of virtually dependent orindependent networks with no interference zone may be calculated as:

channel bandwidth*number of networks.

The total bandwidth used in a dependent network is channel bandwidth.The total bandwidth used in mesh network of virtually dependent networkarray with an interference zone may be calculated as:

channel bandwidth*number of networks−sum(interference zones bandwidth)

Thus, utilizing sync packets as described herein to mark and avoidinterference zones may increase overall channel bandwidth in a meshnetwork.

Example Selection of a Network

A PNC candidate may select which piconet to join in the event that itreceives sync packets transmitted from devices in more than one piconet.According to certain aspects, a PNC candidate may select a network basedon a PNC address field and choose to join the piconet with the lowervalue of the PNC address field. This simple algorithm for synchronizingto the piconet with lower value of the PNC address field may apply fornetwork controllers of an exiting piconet. In this scenario, the PNCwith the higher address may adopt its timing parameters to synchronizeto the piconet with lower value of the PNC address field.

According to certain aspects, in addition to scanning for sync packetsduring piconet creation, a PNC may also periodically scan for syncframes from neighboring piconets. The PNC may update its mapping ofinterference time slots of one or more neighboring piconets and avoidthese interference time slots when allocating resources to its owndevices.

A device may synchronize timing with a piconet multiple times in apiconet lifetime. Synchronizing multiple times allows a device to adjustits timing to account for dynamic changes in the piconet environment,for example, such as dynamic changes in interference as devices drift inand out of network coverage area.

Example Ranging Calculation Using Sync Packet Time Stamps

As described above, a PNC may utilize sync frames to perform rangingoperations to determine a relative location of a device. FIG. 14illustrates an example range calculation using synchronization packettime stamps, in accordance with certain aspects of the presentdisclosure. Station A may use timing information received to calculate atravel time (t′) from the difference between the actual receive time andthe transmit time stamp contained in the synchronization packet:

t′=t2 rx−t2 tx (stamp)

As an illustrative example, assuming a 2.5 Gsps sample rate, thiscalculation may yield a +/−6 cm range accuracy, which may be more thanadequate for many purposes, such as to perform station range adaptation.

One example application for such ranging operations involves wirelessvideo distribution. Wireless video distribution systems may aim toreplace standard cable transmission for video distribution whileproviding adequate performance and reliability.

According to certain aspects, ranging techniques presented herein may beused to adopt at least one of the bandwidth or resolution (i.e., one orboth) of wirelessly distributed video to the range between a wirelessvideo source and a wireless video destination. As illustrated in FIG.15, ranging operations for a destination node that is to receivewirelessly distributed video may be performed, at 1502. At least one ofa bandwidth or resolution of the wirelessly distributed video may beadjusted based on results of the ranging operations, at 1504.

For example, range adaptation may be used to select foregrounduncompressed high definition video display when a wireless video sourceand destination are in close proximity (e.g., Line of Site) forproviding same user experience as wired HDMI cable. Such a rangeadaptation algorithm may control switching to a lower resolution whenthe wireless video source and destination are drawn away to Near Line ofSite (e.g., in room). Such a range adaptation algorithm may also operatea background process for lower bandwidth/lower resolution, for example,when wireless video source and destination are not in the same room(e.g., non line of site) for video distribution in home.

When the video source is in close proximity to video destination (nearline of site) it mat be configured to use maximum bandwith to streamvideo to the video destination (e.g., for display and/or strorage). As aresult, a user may enjoy maximum resolution for display and/or fastestsyncing time. When the video source moves further away from thedestination, the display resoltion can be lower and/or video transfercan seamlessly switch to background process using lower bandwidth.

While the ranging technique described above, based on timestamps insynchronization packets, may be used to determine the proximity of thevideo destination to the video source, any other suitable rangingtechnique may also be used and the bandwidth and/or resolution of thedistributed video may be adapted accordingly.

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrate circuit (ASIC), or processor. Generally,where there are operations illustrated in Figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering. For example, blocks 510-530, 610-640, 1202-1206, and1502-1504 illustrated in FIGS. 5, 6, and 12 correspond to circuit blocks510A-530A, 610A-640A, 1202A-1206A, and 1502A-1504A illustrated in FIGS.5A, 6A, and 12A.

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

As used herein, the term “at least one of a or b” is intended to beinclusive. In other words, “at least one of A or B” includes thefollowing sets {A}, {B}, and {A and B}.

The various operations of methods described above may be performed byany suitable means capable of performing the operations, such as varioushardware and/or software component(s), circuits, and/or module(s).Generally, any operations illustrated in the Figures may be performed bycorresponding functional means capable of performing the operations.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure, and recited in the claimsbelow, may be implemented or performed with a general purpose processor,a digital signal processor (DSP), an application specific integratedcircuit (ASIC), a field programmable gate array signal (FPGA) or otherprogrammable logic device (PLD), discrete gate or transistor logic,discrete hardware components or any combination thereof designed toperform the functions described herein. A general purpose processor maybe a microprocessor, but in the alternative, the processor may be anycommercially available processor, controller, microcontroller or statemachine. A processor may also be implemented as a combination ofcomputing devices, e.g., a combination of a DSP and a microprocessor, aplurality of microprocessors, one or more microprocessors in conjunctionwith a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with thepresent disclosure may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in any form of storage medium that is knownin the art. Some examples of storage media that may be used includerandom access memory (RAM), read only memory (ROM), flash memory, EPROMmemory, EEPROM memory, registers, a hard disk, a removable disk, aCD-ROM and so forth. A software module may comprise a singleinstruction, or many instructions, and may be distributed over severaldifferent code segments, among different programs, and across multiplestorage media. A storage medium may be coupled to a processor such thatthe processor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

The functions described may be implemented in hardware, software,firmware or any combination thereof. If implemented in software, thefunctions may be stored as one or more instructions on acomputer-readable medium. A storage media may be any available mediathat can be accessed by a computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code in the form of instructions or datastructures and that can be accessed by a computer. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein. For certain aspects, the computer program product may includepackaging material.

Software or instructions may also be transmitted over a transmissionmedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition oftransmission medium.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

1. A method of wireless communication, comprising: receiving, from afirst node in a first piconet, a first synchronization packet containingtiming information regarding allocation of resources in the firstpiconet; determining interference time slots corresponding to allocatedtransmissions times for nodes in the first piconet, based on the timinginformation; and establishing a second piconet by allocating availableresources to nodes in the second piconet based on the determinedinterference time slots corresponding to allocated transmissions timesfor the nodes in the first piconet.
 2. The method of claim 1, furthercomprising: periodically monitoring transmissions from nodes in thesecond piconet to detect potential interference with transmissions inthe first piconet; and adjusting the allocation of resources in thesecond piconet to avoid interference with transmissions in the firstpiconet.
 3. The method of claim 1, further comprising: receiving, fromone or more nodes in a third piconet, synchronization packets containingtiming information regarding allocation of resources in the thirdpiconet; determining interference time slots corresponding to allocatedtransmissions times for the nodes in the third piconet, based on thetiming information associated with the third piconet; and adjusting theallocation of resources in the second piconet based on the determinedinterference time slots corresponding to allocated transmissions timesfor the nodes in the third piconet.
 4. The method of claim 3, furthercomprising selecting whether to synchronize to timing of a piconetcoordinator (PNC) of the first piconet or a PNC of the third piconetbased on corresponding PNC address values included in synchronizationpackets received from nodes in the first and third piconets.
 5. Themethod of claim 1, wherein the first node comprises a node that is notacting as a piconet coordinator (PNC).
 6. The method of claim 1, whereinthe first node comprises an access terminal.
 7. The method of claim 1,wherein the first synchronization packet comprises a time stampindicating a start time of a preamble of a frame to be transmitted inthe first piconet.
 8. The method of claim 7, further comprising:performing ranging operations based on a difference between a time whenthe first synchronization packet was received and a time indicated bythe time stamp.
 9. An apparatus for wireless communication, comprising:a receiver configured to receive, from a first node in a first piconet,a first synchronization packet containing timing information regardingallocation of resources in the first piconet; a scheduler configured todetermining interference time slots corresponding to allocatedtransmissions times for nodes in the first piconet, based on the timinginformation; and logic configured to establish a second piconet byallocating available resources to nodes in the second piconet based onthe determined interference time slots corresponding to allocatedtransmissions times for the nodes in the first piconet.
 10. Theapparatus of claim 9, further comprising: logic configured toperiodically monitor transmissions from nodes in the second piconet todetect potential interference with transmissions in the first piconetand adjust the allocation of resources in the second piconet to avoidinterference with transmissions in the first piconet.
 11. The apparatusof claim 9, wherein: the receiver is further configured to receive, fromone or more nodes in a third piconet, synchronization packets containingtiming information regarding allocation of resources in the thirdpiconet; the scheduler is configured to determine interference timeslots corresponding to allocated transmissions times for the nodes inthe third piconet, based on the timing information associated with thethird piconet; and the apparatus further comprises logic configured toadjust the allocation of resources in the second piconet based on thedetermined interference time slots corresponding to allocatedtransmissions times for the nodes in the third piconet.
 12. Theapparatus of claim 11, further comprising logic configured to selectwhether to synchronize to timing of a piconet coordinator (PNC) of thefirst piconet or a PNC of the third piconet based on corresponding PNCaddress values included in synchronization packets received from nodesin the first and third piconets.
 13. The apparatus of claim 9, whereinthe first node comprises a node that is not acting as a piconetcoordinator (PNC).
 14. The apparatus of claim 9, wherein the first nodecomprises an access terminal.
 15. The apparatus of claim 9, wherein thefirst synchronization packet comprises a time stamp indicating a starttime of a preamble of a frame to be transmitted in the first piconet.16. The apparatus of claim 7, further comprising: ranging logicconfigured to perform ranging operations based on a difference between atime when the first synchronization packet was received and a timeindicated by the time stamp.
 17. An apparatus for wirelesscommunication, comprising: means for receiving, from a first node in afirst piconet, a first synchronization packet containing timinginformation regarding allocation of resources in the first piconet;means for determining interference time slots corresponding to allocatedtransmissions times for nodes in the first piconet, based on the timinginformation; and means for establishing a second piconet by allocatingavailable resources to nodes in the second piconet based on thedetermined interference time slots corresponding to allocatedtransmissions times for the nodes in the first piconet.
 18. Theapparatus of claim 17, further comprising: means for periodicallymonitoring transmissions from nodes in the second piconet to detectpotential interference with transmissions in the first piconet; andmeans for adjusting the allocation of resources in the second piconet toavoid interference with transmissions in the first piconet.
 19. Theapparatus of claim 17, further comprising: means for receiving, from oneor more nodes in a third piconet, synchronization packets containingtiming information regarding allocation of resources in the thirdpiconet; means for determining interference time slots corresponding toallocated transmissions times for the nodes in the third piconet, basedon the timing information associated with the third piconet; and meansfor adjusting the allocation of resources in the second piconet based onthe determined interference time slots corresponding to allocatedtransmissions times for the nodes in the third piconet,
 20. Theapparatus of claim 19, further comprising means for selecting whether tosynchronize to timing of a piconet coordinator (PNC) of the firstpiconet or a PNC of the third piconet based on corresponding PNC addressvalues included in synchronization packets received from nodes in thefirst and third piconets.
 21. The apparatus of claim 17, wherein thefirst node comprises a node that is not acting as a piconet coordinator(PNC).
 22. The apparatus of claim 17, wherein the first node comprisesan access terminal.
 23. The apparatus of claim 17, wherein the firstsynchronization packet comprises a time stamp indicating a start time ofa preamble of a frame to be transmitted in the first piconet.
 24. Theapparatus of claim 23, further comprising: means for performing rangingoperations based on a difference between a time when the firstsynchronization packet was received and a time indicated by the timestamp.
 25. A wireless node capable of assuming a role of a PiconetCoordinator (PNC), comprising: at least one antenna; a receiverconfigured to receive via the at least one antenna, from a first node ina first piconet, a first synchronization packet containing timinginformation regarding allocation of resources in the first piconet; ascheduler configured to determining interference time slotscorresponding to allocated transmissions times for nodes in the firstpiconet, based on the timing information; and logic configured toestablish a second piconet by allocating available resources to nodes inthe second piconet based on the determined interference time slotscorresponding to allocated transmissions times for the nodes in thefirst piconet.
 26. A computer-program product for wirelesscommunications, comprising a computer-readable medium comprisinginstructions executable to: receive, from a first node in a firstpiconet, a first synchronization packet containing timing informationregarding allocation of resources in the first piconet; determineinterference time slots corresponding to allocated transmissions timesfor nodes in the first piconet, based on the timing information; andestablish a second piconet by allocating available resources to nodes inthe second piconet based on the determined interference time slotscorresponding to allocated transmissions times for the nodes in thefirst piconet.
 27. A method of wireless communication, comprising:performing ranging operations for a destination node that is to receivewirelessly distributed video; and adjusting at least one of a bandwidthor resolution of the wirelessly distributed video based on results ofthe ranging operations.
 28. The method of claim 27, wherein performingranging operations comprise: receiving, from the destination node, asynchronization packet containing a time stamp indicating a transmissiontime of the synchronization packet; and calculating a result based on adifference between a time when the synchronization packet was receivedand a time indicated by the time stamp.
 29. The method of claim 27,wherein the adjusting comprises: increasing the resolution of thewirelessly distributed video if the results of the ranging operationsindicate a wireless video source and the destination node are inrelatively close proximity to each other.
 30. The method of claim 27,wherein the adjusting comprises: decreasing the resolution of thewirelessly distributed video if the results of the ranging operationsindicate a wireless video source and the destination node are not inrelatively close proximity to each other.
 31. An apparatus for wirelesscommunication, comprising: ranging logic configured to perform rangingoperations for a destination node that is to receive wirelesslydistributed video; and adjusting logic configured to adjust at least oneof a bandwidth or resolution of the wirelessly distributed video basedon results of the ranging operations.
 32. The apparatus of claim 31,wherein the ranging logic is configured to: receive, from thedestination node, a synchronization packet containing a time stampindicating a transmission time of the synchronization packet; andcalculate a result based on a difference between a time when thesynchronization packet was received and a time indicated by the timestamp.
 33. The apparatus of claim 31, wherein the adjusting logic isconfigured to: increase the resolution of the wirelessly distributedvideo if the results of the ranging operations indicate a wireless videosource and the destination node are in relatively close proximity toeach other.
 34. The apparatus of claim 31, wherein the adjusting logicis configured to: decrease the resolution of the wirelessly distributedvideo if the results of the ranging operations indicate a wireless videosource and the destination node are not in relatively close proximity toeach other.
 35. An apparatus for wireless communication, comprising:means for performing ranging operations for a destination node that isto receive wirelessly distributed video; and means for adjusting atleast one of a bandwidth or resolution of the wirelessly distributedvideo based on results of the ranging operations.
 36. The apparatus ofclaim 35, wherein the means for performing ranging is configured to:receive, from the destination node, a synchronization packet containinga time stamp indicating a transmission time of the synchronizationpacket; and calculate a result based on a difference between a time whenthe synchronization packet was received and a time indicated by the timestamp.
 37. The apparatus of claim 35, wherein the means for performingranging is configured to: increase the resolution of the wirelesslydistributed video if the results of the ranging operations indicate awireless video source and the destination node are in relatively closeproximity to each other.
 38. The apparatus of claim 35, wherein themeans for adjusting is configured to: decrease the resolution of thewirelessly distributed video if the results of the ranging operationsindicate a wireless video source and the destination node are not inrelatively close proximity to each other.
 39. A wireless video source,comprising: at least one antenna; ranging logic configured to performranging operations, based on packets received via the at least oneantenna, for a destination node that is to receive wirelesslydistributed video; and adjusting logic configured to adjust at least oneof a bandwidth or resolution of the wirelessly distributed video basedon results of the ranging operations.
 40. A computer-program product forwireless communications, comprising a computer-readable mediumcomprising instructions executable to, comprising: perform rangingoperations for a destination node that is to receive wirelesslydistributed video; and adjust at least one of a bandwidth or resolutionof the wirelessly distributed video based on results of the rangingoperations.